This invention relates to evaporative humidifiers, and more particularly to an apparatus and method for sensing the level of water absorbed within a wick and for indicating the efficiency of the wick.
Humidifiers are often used in environments where it is desirous to raise the level of humidity, particularly in homes or the like during the winter months where the relative humidity may be reduced to an uncomfortable level by the heating system. Under these circumstances, it is beneficial to introduce moisture into the air. Humidifiers of the evaporative type are commonly used for this purpose. Such humidifiers typically include a housing with a reservoir for holding water, a water absorbing material, such as a wick, partially submerged in the water, and a fan attached to the housing for creating airflow through the wick. In use, water is drawn up through the non-immersed portion of the wick by capillary action while airflow through the wick distributes the moisture from the wick to the surrounding atmosphere.
Over time, the wick""s ability to draw water from the reservoir deteriorates, leading to less efficient operation of the humidifier. Accordingly, the wick must be replaced in order to restore the humidifier""s efficiency. Prior attempts to determine the wick""s condition have included physical inspection of the wick and/or monitoring the time period during which the wick is in use. However, it is difficult to determine when the wick should be replaced since these techniques do not assess the actual performance of the wick. By way of example, the wick may change color as a result of the absorption of various minerals over a period of a time. Since the minerals that exist in public or private water supplies can vary from one location to another, replacement guidelines based only on physical inspection and/or time in use fail to adequately assess the condition of the wick and/or its efficiency.
According to one aspect of the invention, a humidifier comprises a reservoir adapted to retain water, an evaporative media in fluid communication with the reservoir, and at least one sensor for detecting temperatures at a plurality of measurement locations along the length of the evaporative media. The evaporative media is adapted to draw water along a length thereof from the reservoir. The humidifier also comprises a controller that is in communication with the at least one sensor for determining a temperature differential between adjacent measurement locations along the length of the evaporative media. The controller generates at least one signal indicative of at least one of evaporative media replacement and evaporative media remaining life when the temperature differential is above a predetermined value.
According to a further aspect of the invention, a sensor assembly for determining a condition of a wick in an evaporative humidifier comprises at least one sensor for detecting temperatures at measurement locations along the wick, and circuitry in communication with the at least one sensor for determining a temperature differential between adjacent measurement locations. The circuitry generates at least one signal indicative of the condition of the wick when the temperature differential is above a predetermined value.
According to an even further aspect of the invention, a method of determining a condition of a wick in an evaporative humidifier comprises measuring a plurality of temperature values at a corresponding plurality of measurement locations along the wick, calculating at least one temperature differential from adjacent temperature values corresponding to adjacent measurement locations, and generating at least one signal indicative of at least one of wick replacement and wick remaining life when the temperature differential is above a predetermined value.